Footwear manufacturers and designers continually strive to find ways to make footwear more comfortable and durable. To this end, inserts and footpads commonly are used in the art to provide shock absorbency, advantageous weight distribution, cushioning, ventilation, and other benefits.
Many of these designs are inserts, which may be used in a previously purchased shoe or boot. For example, U.S. Pat. No. 532,429 describes an elastic heel and sole for boots. The heel and sole consist of cushions, pads, or air cells that are secured to a flexible in-sole, which then is Inserted into a boot.
U.S. Pat. No. 4,345,387 describes an inner sole for use with a shoe having an upper and a sole structure. The inner sole rests upon the upper surface of the sole structure and has a plurality of upwardly extending protrusions, which bend, depress or telescope to conform to the shape of the wearer's foot. When depressed, some air from inside the protrusions will flow between the inner sole and the sole structure; however, most of the air will remain trapped to provide a spring action when the foot is lifted off the ground.
U.S. Pat. No. 4,896,441 describes a removable innersole for footwear. The innersole has the shape of the sole of the shoe and has a plurality of discrete, elements extending toward the sole of the shoe. These elements distribute the weight of the wearer along a surface greater than the sole of the shoe alone.
U.S. Pat. No. 5,197,207 describes a sport or rehabilitation shoe having an insert part formed from elastic compressible material. The insert is positioned in a recess of the shoe sole or midsole in the area of the ball of the foot. This provides the shoe with increased stability for wearers whose feet tend to tilt inwardly.
U.S. Pat. No. 5,367,791 describes a shoe sole insert that includes downwardly extending foam-filled compressible regions. The insert is housed between a midsole and an insole board.
U.S. Pat. No. 5,983,529 describes a shock absorbing cassette to be inserted between the outer sole and midsole of a shoe, preferably to be used by skateboarders. The cassette includes a base and sets of deformable cushion elements.
U.S. Pat. No. 6,138,383 describes an insert for a conventional walking or running shoe. The insert includes cavities formed in the insert bottom face that provide a spring action at a point of impact or applied force.
U.S. Pat. No. 6,178,662 describes a footpad for use in a sole, insole, or heel. The footpad includes a plurality of resilient lugs. The side surfaces of the lugs define therebetween a void which extends lattice-like over the footpad. The lugs transmit downward pressure to the pad from which they extend. The volume between adjacent lugs decreases as downward pressure is applied. Fluid, such as a gas, a liquid, or a viscous or a plastic material, also may be incorporated in the lugs.
U.S. Pat. No. 6,367,172 describes a shoe for active wear including an outsole, padding, an insole and an upper. A cavity is formed in the outer sole with the padding adhesively bonded therein.
U.S. Pat. No. 6,425,194 B1 describes a cushioning insole specifically designed based on the foot of the wearer. Using a pressure map of the wearer's foot, the cushioning insole is created. The insole has a central layer whose upper surface conforms to the wearer's foot. The bottom surface of the central layer has a layout of spaced apart pressure receiving fingers. Each finger has a predetermined height and diameter such that the fingers as a whole optimally suit the pressure map of the foot.
U.S. Des. 298,583 shows a midsole having an upper surface that cradles the foot of the wearer and a bottom surface having a plurality of downwardly extending protrusions.
While providing potential benefits to the wearer, the above-described inserts are designed to be placed in conventional footwear. None of these patents disclose footwear having a specially designed sole that, rather than being an insert or an addition, is the actual sole of the footwear.
U.S. Pat. No. 5,619,809 does describe a sole assembly for providing air circulation around the foot. This sole assembly, however, is a somewhat complicated assembly including five separate components. These components include an outsole, an insert, a conventional insole, and an orthotic. The insert is suspended above the outsole to provide an air chamber. A plurality of pins extending downwardly from the insert correspond to opening pockets in the outsole. When depressed (i.e., when subjected to a load), the pins deform and fill the pockets. When the pockets are filled, further deformation of the pins is restricted by the walls of the pockets enabling the sole assembly to resist high impact forces.
U.S. Pat. No. 6,560,900 B2 describes a sole having a honeycomb pattern and a vamp connected thereto. The sole includes a vertical extending sidewall to which the vamp is sewn. The height of the sidewall must be sufficient to provide a lip for stitching to the vamp's lower perimeter.
Sewing of an upper to a sole as described with respect to the '900 patent can be difficult and time-consuming. An improvement for sewing a sole to an upper is disclosed in U.S. Ser. No. 10/200,856, by Michael H. Ganon now U.S. Pat. No. 6,666,157, the disclosure of which is hereby incorporated by reference. In that patent, method and apparatus are disclosed wherein a basic flatbed sewing machine design is converted for sewing through a thick workpiece such as a molded rubber or elastomeric sole having a sewing rim extending generally horizontally from either its top or bottom surface. To connect such a sole with an upper by a stitching procedure, the design facilitates the operational tasks of the sewing machine operator, permitting the holding of the two pieces to be joined with both hands and permitting the thus joined and aligned assemblage to be held down against a work surface as well as an upstanding guide surface. This arrangement achieves both accurate and desirably positioned stitching and results in less operator fatigue and substantial minimization of any opportunity for “kick-out” of the workpieces being joined together.
With the approach of the invention, preexisting basic sewing machines can be retrofitted very simply, for example, using a screwdriver, at relatively low cost inasmuch as the drive mechanisms of the basic machine, for example, incorporating cam actuation and the like are not altered. Correspondingly, the stroke of the machine is not altered. Thus, sewing machines with which operators are already familiar may be retrofitted for the production of footwear such as slippers or the like with relatively thick molded rubber soles and cloth uppers for a given production interval, for example, three months. Following that interval, the machines readily are converted back to their original structuring for production of a next product. As a consequence of the resultant low cost tooling for these specific products, cost of the products themselves are substantially reduced to the extent that superior products are cost competitive with preexisting inferior ones.
The method and apparatus disclosed in the '157 patent enables rubber or elastomeric soles to be easily sewn to an upper. Eastomeric soles for use with the converted sewing machine of the '157 patent continue to be sought.